9317 ‎(2)‎

• UCREFRP Catalog Number: 9317
• Author: Spahr, N. E., L. E. Apodaca, J. R. Deacon, J. B. Bails, N. C. Bauch, C. M. Smith and N. E. Driver.
• Title: Water Quality in the Upper Colorado River Basin, Colorado, 1996-98.
• USFW Year: 2000.
• USFW - Doc Type: Denver.
• Copyright Material: NO

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Oa: 40 Qw
zw 3.5 micrograms per gram I-a. 315 micrograms per gram
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Figure 11. Median concentrations of cadmium and zinc in streambed sediments were greater than the Canadian Probable
Effect Level in most mining districts of the UCOL.

nity composition from sensitive
insects, such as mayflies, to more
tolerant insects, such as midges.
Lower mayfly abundance can be
related to increased trace-element
concentrations (Clements and
Kiffney, 1995; Clements, 1994;

Kiffney and Clements, 1994).
Concentrations of trace elements in
transplanted aquatic moss also pro-
vide information about the occur-
rence and bioavailability of trace
elements (Carter and Porter, 1997).
In order to assess the source(s)
and environmental effects of trace

elements, a more detailed study
was conducted in the Blue River
Basin; this study included the col-
lection of water, streambed sedi-
ments, reservoir sediments, and
aquatic moss samples and an
assessment of the habitat and inver-
tebrate communities.

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100,000

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MINIMUM

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100

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. NATIONAL
. UCOL

I

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t

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CADMIUM

ZINC

COPPER

LEAD

The median concentrations for cadmium, copper, lead, and zinc in streambed sediment from sites in the
UCOL were higher than the median concentrations of the same trace elements sampled in other Study Units
of the national NAWQA Program. The data available on trace elements include 541 samples from the
NAWQA Study Units (Rice, 1999) and 37 samples from theUCOL. Mineralized areas and historical mining
activities in the UCOL have resulted in higher concentrations of some trace elements in streams than those
concentrations that typically are found in other parts of the United States.

12 Water Quality in the Upper Colorado River Basin